1. Field of the Invention
The present application relates to optical sensors and more particularly to optical sensors having multiple fields of view.
2. Brief Description of Related Art
Modern high-resolution wide field of view (FOV) imaging systems are important tools for large area observation and target tracking. Recording high-resolution data over a wide FOV allows any number of targets within the imaging system's large observable area to be individually tracked by digitally zooming in on each target within the image. However, such imaging systems often generate an overwhelming quantity of data, limiting their use to large, expensive host platforms with powerful processing systems. Unfortunately, many desirable host platforms are smaller, less expensive, and possess insufficient processing power to operate such tracking systems.
There are two traditional alternatives to such high-resolution wide FOV imaging systems. First, a lower-resolution wide FOV camera can be used to capture data. Unfortunately, while this alternative is acceptable for tracking trucks, cars, and other larger objects, the lower resolution is insufficient for tracking smaller objects such as people or bicycles. The second traditional alternative is to capture high-resolution data over a narrower FOV. This method is disadvantageous because targets can be tracked only in a small area and once a target leaves the area covered by the narrow FOV, or multiple targets move in opposite directions, at least one of the targets is lost. Losing targets and inability to track smaller targets are undesirable traits, especially in a military context where losing a target can mean an enemy combatant or known terrorist escapes capture.
The traditional solution to this problem is to create a highly complex telecentric lens to direct the light from all directions onto the flat focal plane to obtain a very wide FOV. However, this can increase lens complexity by requiring double or more the number of elements of a typical standard lens. Such increased complexity severely increases production times, costs, and loss rates. All of these disadvantages are multiplied by the number of lenses in the system, making wide FOV systems highly expensive and difficult to make for low cost and high volume applications, such as cell phone cameras.